particles and waves (part 1) Flashcards
what is a magnetic field?
produced when currents flow through a wire
what do particle accelerators do?
accelerate elementary particles to very high energies (electrons or protons)
3 types of particle accelerators
linear accelerator
cyclotron
synchrotron
how particle accelerators work
use electric fields to speedup and increase energy of a beam of particles
electromagnets are used to keep beam of particles confined within accelerator
beam is accelerated within a vacuum as any air or dust particles would obstruct its path
2 purposes of particle accelerators
research into fundamental particles
electron beams used to alter properties of plastics or harden surfaces
3 medical purposes of particle accelerators
producing radioisotopes
producing electrons and protons for medical treatment
medical sterilisation
what is all matter made from
fermions
4 types of bosons and their associations
gluon (strong force)
w and z bosons (weak nuclear force)
graviton (gravitational force)
photon (electromagnetic force)
2 bosons with short range and where they act
gluon (acts between quarks)
w and z bosons (acts between leptons)
2 bosons with infinite range
graviton
photon
2 types of fermions
leptons
quarks
4 types of leptons
electron
muon
tau
neutrino
6 types of quarks
up
down
strange
charm
top
bottom
what do quarks combine to form?
hadrons
2 types of hadrons
baryons
mesons
baryon factfile
made up of 3 quarks
e.g. protons and neutrons
stable
meson factfile
made up of 1 quark and 1 antiquark
e.g. pions and kaons
unstable
what evidence is there for the existence of quarks?
high energy collisions between electrons and nucleons
(particles found in the nucleus, e.g. protons)
3 quarks with +2/3 charge
up
charm
top
3 quarks with -1/3 charge
down
strange
bottom
what are leptons?
fundamental particles that cannot be broken down into other particles
what do muons and taus do?
unstable and decay into electrons
neutrino fact file
beta decay first evidence of neutrino
no charge so don’t interact with any other particle
mostly produced in particle decay
what happens when a particle and its antiparticle meet?
annihilate each other
mass turns to energy
this energy forms other particles
example of particle and antiparticle annihilation
electron and positron form 2 photons
4 fundamental forces
strong nuclear
weak nuclear
gravity
electromagnetic
2 purposes of strong nuclear force
holds quarks together to form hadrons
holds particles of same charge together
what is the weak nuclear force involved in?
beta decay
2 purposes of electromagnetic force
stops electrons being ejected from atom
force between electronically charge particles (ions)
purpose of gravitational force
attract particles that have mass and holds matter together
weakest fundamental force
what does the mass number represent?
total number of protons and neutrons in the nucleus
what does the atomic number represent?
total number of protons
what are isotopes of an element?
same atomic number, different mass number
what happens in alpha decay?
atomic number decreases by 2
mass number decreases by 4
(most ionising of all nuclear decay)
what happens in beta decay?
mass number unchanged
atomic number increases by 1
what happens in gamma decay?
atomic and mass numbers unchanged
often also involves gamma radiation
what is nuclear fission?
breaking up of a large nucleus into smaller nuclei
2 types of fission
spontaneous fission- nucleus breaks down without external influence
induced fission- nucleus breaks down after being bombarded with a neutron
what takes place in a nuclear reactor?
induced fission as a neutron is fired at a uranium nucleus, breaking it into two parts- releasing further neutrons and energy
mass and atomic number conserved
what happens when you accurately compare masses before and after fission?
mass before fission is greater than total mass of products
what is nuclear fusion?
two small nuclei fuse to create one larger nuclei + energy
what 2 things is fusion responsible for?
powers stars at very high pressures and temperatures
all elements of universe were formed from original simple particles present in the big bang
example of nuclear fusion`
in the suns core, hydrogen nuclei fuse to form helium nuclei and release vast amounts of energy
how is energy released in E=mc^2
mass lost is converted to energy
